On the influence of vias on a PCB power-bus

In this paper, a method for the investigation of the influence of a through-hole via on a printed circuit board power-bus is presented. Therefore based on an introduced via model for a through-hole via its scattering parameters are extracted using a de-embedding algorithm. After the following calculation of the via model elements with the two-port theory, the extracted impedances are inserted in a known formula for the power-bus impedance. In addition, it is shown how the signal return current acts as an excitation source of the waveguide modes within the power-bus.